Abstract

Proton transfer mechanism between DNA nucleobases in biological system is a well-established natural
phenomenon. Again it is experimentally established that the anticancer drugs directly bind with DNA nucleobases
with different types of interactions. During these interactions, the proton transfer mechanism between nucleobases
of DNA (adenine-thymine [AT] and guanine-cytosine [GC]) may be slightly changed. The proton transfer
mechanism within DNA nucleobases, GC, and AT base pairs had been studied for normal base pairs and drug-
base pair stacked models. Theoretically, it was observed that the stacking interactions of drugs with base pair
of DNA results change in the proton transfer energies. The mechanism of proton transfer may also change the
acid-base characteristics of nucleobase during proton transfer. Due to the stacking interaction between drug
chromophore and nucleobase, the barrier of proton transfer energies might have changed, and it also indicates
the shifting of equilibrium proton transfer between counter nucleobases.